1. Field of the Invention
The present invention relates generally to a gas discharge display device, and more specifically a gas discharge display device operable with a low discharge voltage and having the construction that the cathode surrounding relationship with the discharge space of the anode.
2. Description of the prior Arts
In a known gas discharge device as shown in FIG. 1, a plurality of barriers 3 are spaced apart between the upper plate glass 1 and the lower plate glass 2, the discharge space 6 is defined between the anode 4 and the cathode 5 respectively arranged in a pattern to extend orthogonally of each other on the internal surfaces of said upper and lower plate glasses 1, 2. The discharge space 6 has a construction for sealing an inert gas, and if voltage is applied to said anode 4 and said cathode 5, an electron emits from the cathode 5 and collides with the inert gas in the discharge space 6 to thereby light the character to be displayed.
When discharging such as above, due to the phenomenon of sputtering in the cathode 5, damage to and loss of the cathode occurs. As a conventional cathode 5 has a strip shape, the electron emission of the cathode is not done well during the sputtering phenomenon, and consequently it is a problem that the life of the cathode is shortened.
To solve problems as above, it is well known that mercury is used but does harm to a person. Since the dangerousness of process and usage is latent, the method as above is undesirous.
Alternatively, in U.S. Pat. No. 3,849,688 the first electrode and the second electrode are arranged at different vertical heights, and the second electrode has triangular ribs thereon.
Particularly, the conventional cathode construction is such that the light is generated in discharging when atoms of a metastable state are moved by diffusion, and because the probability to move them in the cathode is very small and the expectation of electron emission is very small, it is a defect that the high discharge voltage is required.
Alternatively, when the conventional barrier construction is formed in the print method, the alignment and the print process are very difficult because the cathode is processed independently.